1. Field of the Invention
The present invention relates to a dual chamber system and method to calibrate sensors and devices. In particular, the present invention relates to generating quality steam for calibrating a sensor. More particularly, the present invention relates to a dual chamber system to determine known parameters of steam at a location, where a device is to be calibrated at the location.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
There are many technologies in the oil and gas industry to increasing the amount of oil extracted from an oil field. More efficient extraction results in less waste and greater yield. With new technology, previously spent oil fields or even low producing oil fields can be reinvigorated for new production or extended production. Enhanced Oil Recovery (EOR) includes those techniques for increasing or improving the extraction of oil from an oil field.
Generally, the methods for enhanced oil recovery include heating the hydrocarbons, including crude oil, bitumen, and liquid natural gas, in the ground formation to lower viscosity for easier pumping. Additional heat reduces surface tension and increases permeability. For some EOR, the hydrocarbons are vaporized, which also facilitates the extraction from the formation. Vaporized oil can be condensed later for a cleaner hydrocarbon with fewer impurities.
Examples of EOR techniques include steam flooding or steam injection and steam assisted gravity drainage. Steam injection involves cyclically pumping steam into a well. The steam condenses to hot water, which heats the oil or evaporates the oil. The hotter oil has less viscosity and pumps easier for extraction. The evaporated oil can be collected and condensed into a cleaner oil composition later. Steam injection can be applied to relatively shallow wells and relatively dirty hydrocarbons, such as heavy crude oil and bitumen. Steam Assisted Gravity Drainage (SAGD) is a more complex utilization of steam to recover more hydrocarbons. In SAGD, two horizontal wells are drilled into an oil reservoir, without one horizontal well above the other horizontal well. High pressure steam is injected through the upper horizontal well, and the more fluid oil drains into the lower horizontal well for extraction. SAGD is used for even tougher and dirtier heavy crude oils and oil sands.
There are existing means of producing steam for enhanced oil recovery techniques, including steam boilers and steam calibration loops. Steam boilers are well known as being a heated vessel capable of boiling water, often at high pressure and thus increased temperature. Steam calibration loops are also used to provide steam for other applications. Determining the properties of the steam generated is important for managing and controlling the EOR process. The steam generated is measured by instruments during EOR processes.
There is a need to calibrate these instruments for sensing and detecting steam. For example, one instrument is a flow meter. The flow meter for wet steam can be calibrated, as disclosed in the article by Hussein et al. [Flow Meas. Instrum., Vol. 2, October, 1991, p. 209-215]. In the experimental apparatus the saturated steam is superheated in a superheater. To generate wet steam, water is injected into the superheated steam via a set of fine sprays. From the knowledge of the water and total steam flow rates, and the temperatures and pressures of the superheated steam and the water, an energy balance can be used to calculate the final steam dryness fraction. The wet steam flow loop was metrologically certified and was used to calibrate different wet steam flow meters. The wet steam correction factors were determined for several industrial steam flow meters.
The system for accurate measurement of steam flow rate, dryness fraction, i.e. steam quality factors, was disclosed in the article by Hussein et al. [Flow Meas. Instrum., Vol. 3, No. 4, 1992, p. 235-240]. The system consists of a separator and condensate flowmeter followed by a steam flowmeter. Testing of the energy metering system showed that the average differences between the displayed output of the system and the values obtained using a condensate weight tank was about 0.22% for the dryness fraction and 1.05% for the saturated steam flow rate.
Another wet steam flowrate calibration facility is disclosed by Ishibashi et al. [Proceedings of the ASME-JSME-KSME Joint Fluids Engineering Conference, Jul. 24-29, 2011, Hamamatsu, Shizuoka, Japan, 2011, p. 1-6]. The facility has a closed loop in which boilers generate a steam flow up to 800 kg/h. Steam can be generated at a pressure up to 1.6 MPa. The saturated steam generated by two boilers in the loop is super-heated by a heater, then a cooling system controls the wetness, which is calculated from the enthalpy drawn from the superheated steam using the temperature difference and water flowrate in the cooling system. After passing the calibration line, the wet steam is totally cooled down into the water phase then the water flowrate is measured by a Coriolis flowmeter kept at the ambient temperature. All the dominating measuring instruments were calibrated and traceable to the national standards. The facility can measure the total flowrate with error of 0.57% and the steam [gaseous] flowrate with error 0.61%, while steam dryness fraction error is 0.10%.
Generally, prior art calibrated wet steam generators use a flow loop structure. The steam quality is changed either by mixing the superheated steam with water, or by cooling the superheated steam to a predetermined temperature.
It is an object of the present invention to provide an embodiment of a system to calibrate instruments measuring the steam from a steam boiler or steam calibration loop.
It is an object of the present invention to provide an embodiment of a system to calibrate instruments for measuring steam with steam.
It is an object of the present invention to provide an embodiment of a dual chamber system to calibrate instruments for measuring steam.
It is an object of the present invention to provide an embodiment of a dual chamber system to generate a condensed steam with a known quality to calibrate instruments for measuring steam.
It is another object of the present invention to provide an embodiment of a method of generating a condensed steam with a known quality to calibrate instruments for measuring steam.
These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification.